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OOOOThe  Boston  Computer  Society 


SINCLAIR/TIMEX  USER  GROUP  NEWSLETTER 


Volume  2,  Issue  9  September  1983 

This  newsletter  is  produced  to  inform  group  members  of  the  agenda  and 
logistics  for  future  meetings,  as  well  as  to  recap  and  amplify  the  information 
provided  ^tt  the  last  meeting.  It  also  provides  a  forum  for  members  and 
interested  parties  to  communicate  what  they  have  learned  or  developed  relating 
to  Sinclair  and  Timex  computer  products.  Meetings  are  open  to  the  public; 
however,  attendees  are  encouraged  to  join  the  Boston  Computer  Society  (BCS). 
This  newsletter  is  free  to  members.  Back  issues  are  one  dollar  each. 


USER  GROUP  MEETING 


Date:  Wednesday,  September  21,  1983 

Time:  7:00  p.m. 

Place:  Large  Science  Auditorium 

UMass ,  Harbor  Campus 
(Directions  on  last  page) 


SPECIAL 

ANNIVERSARY 

CELEBRATION 

IN 

OCTOBER 


Frank  Kaplan  from  Compusa  Corporation  of  Mountain  Side,  New  Jersey 
(formerly  Centronic  Corporation)  will  be  at  our  meeting  to  describe  the  floppy 
disk  system  his  company  has  developed  for  the  T/S  1000.  The  system  consists 
of  a  disk  controller  compatible  with  many  different  types  of  disks,  a  floppy 
disk  drive  and  case,  power  supplies,  T/S  1000  software,  and  documentation, 
tested  and  ready  to  go.  He  will  make  a  special  preproduction  offer  to  members 
at  the  meeting — the  entire  package  for  around  $450.  Additionally,  Jeff  Parker 
will  review  the  MD1  and  MD2  modem  from  ByteBack. 


IMPORTANT  NOTICE 

Instead  of  our  regular  meeting  in  October,  we  will  be  having  a  special 
event  Saturday,  October  22nd,  from  10  a.m.  till  6  p.m.  at  the  Boston  Park 
Plaza  Hotel.  This  will  celebrate  the  second  anniversary  of  our  user  group. 

We  will  not  only  be  acknowledging  the  accomplishments  and  achievements  of  the 
group  and  its  individual  members,  but  we  will  also  be  examining  the  numerous 
ways  in  which  the  Sinclair  and  Timex  computers  can  and  are  being  used — in 
business,  home,  education,  computer  literacy,  and  entertainment. 

There  will  be  the  opportunity  for  you  to  see  and  buy  items  from  vendors 
that  support,  and  are  compatible  with,  Sinclair  and  Timex  computers,  including 
hardware,  software,  publications,  and  services.  There  will  also  be  workshops 
and  demonstrations  on  various  applications,  and  lectures  on  topics  related  to 
the  Sinclair  and  Timex  computers.  For  an  informative  and  stimulating  day  for 
the  whole  family,  please  come  and  help  us  celebrate.  Details  inside. 


HIGHLIGHTS  OF  THE  AUGUST  MEETING 


The  August  meeting  turned  out  to  be  a  very  busy  meeting.  It  featured  two 
software  reviews,  a  hardware  review,  demonstrations  of  T/S  1500  and  T/S  2068 
computers,  and  announcements. 

Brint  Jefferis  gave  us  a  very  interesting  review  of  ToolKit,  a  $14.95 
software  item  from  Gladstone  Electronics,  Buffalo,  New  York.  He  described 
several  of  the  nine  functions  provided  by  the  software,  including  a  BASIC  line 
renumbering  function  which  even  changes  line  numbers  in  GOTOs  and  GOSUBs. 

Brint  found  ToolKit  easy  to  use.  He  cautioned  that,  because  ToolKit  must  be 
located  above  RAMTOP ,  it  is  not  compatible  with  some  software,  such  as  QSAVE. 

Jack  Hill  next  described  Master  Math,  a  series  of  high  school  math 
quizzes  from  PMI.  See  Jack's  review  later  in  this  newsletter.  The  entire  set 
of  quizzes  were  donated  to  the  BCS  for  our  review  arid  evaluation. 

Burt  Fisher  reviewed  VOTEM,  an  analog  interface  for  our  computer.  Burt 
says  he  is  very  compulsive  about  knowing  the  exact  temperature  and  VOTEM  is 
just  what  he  wanted.  See  his  review  in  this  issue. 

Sue  Mahoney  demonstrated  preproduction  models  of  the  T/S  1500  and  the 
T/S  2068.  The  T/S  1500,  which  will  sell  for  $79.95,  has  been  delayed  pending 
FCC  approval.  Sue  said  it  should  be  available  in  September  or  October. 
According  to  Sue,  the  T/S  1500  is  basically  a  T/S  1000  plus  16K  RAM  in  a 
single  package.  It  features  movable  keys  and  the  capability  of  working  with 
the  16K  RAM  pack  to  give  32K  of  user  memory.  It  will  also  be  capable  of  using 
"solid  state"  ROM  cartridges  which  plug  into  a  special  holder.  The  cartridge 
holder  module  should  cost  less  than  $20. 

The  T/S  2068,  which  is  the  Timex  version  of  the  Spectrum,  comes  in  an 
attractive  silver  box,  with  an  easy  to  use  keyboard,  edge  connector  for 
expansion,  a  17.3  volt  power  supply,  both  television  and  monitor  output,  a 
"solid-state"  cartridge  slot,  and  two  Atari  type  joystick  ports,  one  on  each 
side.  It  features  both  color  video  and  sound.  In  addition  to  the  familiar 
Sinclair  BASIC,  there  is:  a  command  to  VERIFY  that  programs  were  SAVEd 
properly  without  LOADing  and  thereby  erasing  the  program;  multiple  statements 
per  line,  each  statement  separated  by  a  colon;  a  prompt  option  for  the  INPUT 
statement;  the  capability  to  SAVE  and  LOAD  data,  variables,  and  memory  blocks, 
as  well  as  to  MERGE  BASIC  code;  DATA,  READ,  and  RESTORE  statements;  programmed 
recovery  from  errors  with  an  ON  ERROR  command;  and  more.  The  graphics  is  much 
higher  resolution  than  that  of  the  T/S  1000.  And  there  are  convenient 
commands  to  draw  lines,  circles,  and  arcs  of  a  circle.  The  reaction  from  a 
skeptical  audience  was  one  of  delight;  the  T/S  2068  looks  like  a  fun  machine. 

In  other  Timex  related  discussion,  Sue  stated  that  all  Timex  products 
will  be  available  via  mail  order.  The  cost  will  be  the  suggested  retail  price 
plus  a  5  percent  handling  charge  for  hardware  and  a  10  percent  handling  charge 
for  software.  (We  didn't  ask  in  which  category  the  "solid  state"  cartridges 
belong.)  The  Timex  printer  will  work  with  both  the  T/S  1500  and  T/S  2068. 

The  Timex  modem  will  be  developed,  but  will  probably  not  be  available  until 
late  fall.  It  is  still  forecast  to  cost  around  $100.  Sue  also  introduced 
Paul  Schirloff,  editor  of  Timex'  newsletter  Ramb lings . 

A1  Cloutier  (he's  the  person  pictured  next  to  Cliff  Danielson  on  the 
first  page  of  the  July  newsletter)  says  he  needs  some  help  charting  a  course 
through  the  game  Inca  Curse.  He  wants  to  exchange  maps  and  information.  It 
sounds  like  an  interesting  game. 


2 


WE  NEED  VOLUNTEERS ! ! ! 


Our  anniversary  celebration  represents  the  largest  undertaking  of  the 
group  so  far.  The  success  of  this  event  depends  on  help  and  support  from  each 
of  you.  We  need  people  to  do  many  tasks,  some  of  which  involve  work  before 
the  event  and  the  majority  of  which  involve  support  during  the  event.  Some  of 
the  tasks  include  contacting  various  speakers,  coordinating  seminars,  mailing 
announcements,  addressing  envelopes,  making  signs,  posting  signs  and  posters, 
selling  tickets  at  the  door,  running  the  BCS  membership  booth,  designing  and 
producing  the  printed  program,  setting  up  the  rooms,  and  monitoring  and 
explaining  the  displays.  In  addition  to  your  time,  we  need  the  loan  of 
computers,  tape  recorders,  and  television  sets  for  use  at  the  different 
seminars.  Contact  Sue  Mahoney,  Will  Stackman  (666-8626),  or  Jack  Hodgson  at 
the  September  meeting  or  during  the  next  few  weeks  to  get  things  rolling. 

Outline  of  the  Event 

In  the  Terrace  Room  of  the  Park  Plaza  Hotel,  vendors  will  have  booths  at 
which  they  will  be  demonstrating  and  selling  their  products.  We  are 
anticipating  a  good  representation  frotn  vendors,  including  many  who  are  coming 
from  out  of  state.  Additionally,  there  will  be  displays  and  exhibits  relating 
to  our  computer  and  projects  by  members.  Feel  free  to  contribute. 

In  other  rooms  in  the  hotel,  we  will  present  continuing  workshops  and 
seminars  on  various  topics  including;  the  use  of  the  computer  in  the 
classroom,  home  and  business  applications,  computer  literacy  programs,  and 
individual  presentations  from  members.  We  are  still  in  the  process  of 
developing  these  seminars.  If  you  have  an  interesting  application,  please 
contact  us  to  get  on  the  program. 

To  finance  the  event,  we  will  be  charging  vendors  for  space  and  there 
will  be  a  small  admission:  $1  for  BCS  members,  $2  for  students,  $3  for 
general  admission,  and  $5  for  families.  Thanks  to  a  loan  from  Reston 
Publishing  Company,  we  have  been  able  to  reserve  the  room  and  launch  the 
effort.  Even  with  this  format,  we  must  have  a  large  user  group  participation 
to  ensure  success.  Incidentally,  your  participation  will  gain  you  free 
admission. 


MACHINE  LANGUAGE  GROUP  ACTIVITIES 

The  Sinclair-Timex  Machine  Language  Group  meets  on  the  first  Wednesday  of 
each  month.  Contact  Bob  Heath  at  (617)  276-2424  (work)  for  details. 

At  the  August  meeting,  Dave  Miller  demonstrated  one  of  his  computer 
systems  and  several  programs.  Dave's  system  features  the  DK  Tronics  keyboard, 
Memotech  64K  RAM  pack.  Hunter  8K  nonvolatile  RAM,  and  QSAVE  cassette  tape 
loading  system  from  Intercomputer.  Dave  says  his  keyboard  has  a  good  feel, 
but  the  stick-on  labels  to  identify  the  keys  tend  to  wear  out.  He  especially 
likes  the  numeric  key  pad  to  the  right  of  the  regular  keys  on  the  DK  Tronics 
keyboard.  His  demonstration  with  the  Hunter  nonvolatile  was  impressive  in 
that  the  machine  language  programs  he  loaded  into  it  at  home  were  still  there 
when  he  arrived  at  the  meeting. 

Dave  has  made  several  modifications  to  the  basic  hardware,  including: 
installing  a  play/record  switch  for  the  cassette  interface,  adding  a  circuit 
to  allow  machine  code  to  be  executed  in  the  32  to  48K  region,  adding  memory 
decode  and  write  protect  circuitry  to  the  Hunter  board,  and  putting  heat  sinks 
on  the  regulator  and  ULA  chip. 


3 


MACHINE  LANGUAGE  GROUP  (Continued) 


Programs  demonstrated  by  Dave  included  Hot  Z  from  Sinware,  ToolKit,  and 
machine  language  routines  to  load  and  move  blocks  of  memory  as  well  as  create 
large  empty  REM  statements  to  store  machine  code.  Hot  Z  is  a  program  for 
debugging  and  disassembling  machine  language  code.  It  is  especially 
interesting  in  that  it  automatically  recognizes  references  to  the  system 
variables  and  inserts  the  system  variable  mnemonic  in  place  of  the  address  in 
the  disassembled  code. 

Following  Dave's  presentation,  Dave  Wood  briefly  described  the  word 
processor  he  is  developing.  Dave  has  modified  the  machine  language  subroutine 
which  scans  the  keyboard  and  generates  the  television  display.  He  promised  to 
show  us  his  flashing  cursor  at  an  upcoming  meeting* 


CLIVE  SINCLAIR  SPONSORS  HALF  MARATHON  by  Beth  Elliott 

The  Cambridge  Festival  second  annual  Half  Marathon,  sponsored  by  Sinclair 
Research,  Ltd.,  was  held  on  Sunday,  July  17,  with  approximately  1700  runners 
participating.  Encircling  the  city  of  Cambridge,  England,  home  of  Sinclair 
Research,  the  race  followed  a  2-lap ,  13  plus  mile  course.  The  event  was  held 
as  part  of  a  full  week  of  activities  at  the  Cambridge  Festival. 

The  day  promised  to  be  extremely  hot  and  humid  and  even  necessitated 
advancing  the  official  start  time  from  10:00  a.m.  to  7:30  a.m.  This  was  a 
precautionary  measure  taken  on  the  advice  of  medical  authorities  and  city 
officials  to  protect  runners  from  the  midday  heat.  However,  moving  the  start 
time  was  easier  said  than  done.  The  race  organizers  assisted  by  Sinclair 
Research  staff  (this  author  included)  spent  Saturday  afternoon  phoning  each  of 
the  over  2000  race  entrants.  Local  radio,  newspaper,  and  television 
announcements  also  helped  get  the  word  out.  Needless  to  say,  a  few  didn't  get 
the  word  and  there  were  about  50  disappointed  runners  who  showed  up  at  10:00. 

Among  the  early  morning  participants  was  our  own  recently  knighted  Sir 
Clive  Sinclair,  running  enthusiast  extraordinaire .  Clive  had  just  passed  his 
43rd  birthday  four  days  prior  to  the  race.  Happy  Birthday  Sir  Clive!  Also 
participating  in  the  run  were  Leonie  Baldwin  and  Beth  Elliott,  both  of  the 
Sinclair  Research  office  in  Boston. 

Official  finishing  times  are  not  yet  in,  but  Leonie  and  Beth  both  zoomed 
into  the  finish  just  minutes  ahead  of  Clive  in  approximately  1  hour  45 
minutes.  We  have  Clive  placing  an  impressive  949  out  of  the  1700.  This 
year's  winner  Bob  Treadwell  completed  the  course  in  just  1  hour  4  minutes 
36  seconds.  The  first  woman  to  cross  the  line  was  Joyce  Smith,  the  English 
world-class  runner  who  finished  in  1  hour  13  minutes  53  seconds.  Ron 
Pickering,  the  "Howard  Cosell  of  Great  Britain,"  emceed  the  event.  From  his 
platform  at  the  finish  line,  in  true  relentless  sportscaster  fashion,  he 
rustled  up  enthusiasm  to  cheer  Sir  Clive  and  others  into  the  home  stretch  and 
across  the  finish  line. 

Following  the  race,  competitors  and  supporters  from  the  English  and  U.S. 
Sinclair  Research  offices  attended  a  relaxed  garden  party  at  the  Stone  House, 
Clive's  Cambridge  residence.  Familiar  faces  at  the  party  included  Nigel 
Searle,  former  Sinclair-Research  marketing  director  in  the  U.S.,  and  Mary 
Reinman,  former  PR  representative  for  Sinclair  Research  in  the  U.S.  Both  are 
now  working  for  Sinclair  Research  in  the  U.K.  We  all  had  a  wonderfully 
exhausting  weekend.  Thanks  go  out  to  Clive  for  sponsoring  a  terrific  sports 
event . 


4 


MARATHON  OPERATING  TIMES  FOR  THE  TIMEX-SINCLAIR  by  Dave  Miller 


I  have  had  trouble  keeping  my  four  ZX-81  and  T/S  1000  computers  running 
for  more  than  7  or  8  hours.  They  would  quit  at  the  most  inopportune  times. 

I  suspected  high  temperature  problems  and,  therefore,  made  several  changes  so 
that  the  computers  ran  cooler.  Here's  what  I  did  with  each  computer  and  a 
summary  of  my  success. 


The  first  thing  that  I  tried  was  building  a  custom  regulated  power  supply 
for  my  first  computer.  Also,  when  I  installed  the  power  supply,  I  bolted  the 
computer  to  a  stand  with  more  space  under  it  than  normally  provided  by  its 
pads.  This  serves  to  increase  the  air  supply  to  the  vents  underneath  the 
computer.  These  measures  kept  the  computer  working  all  day  and  sometimes 
several  days,  but  it  usually  quit  before  the  end  of  the  third  day. 

My  second  computer  has  a  custom  built  power  supply  but,  in  addition,  has 
the  5-volt  regulator  mounted  on  a  large  metal  chassis.  This  regulator  stays 
very  cool.  This  computer  stayed  up  for  at  least  28  hours  before  quitting. 

My  third  computer,  as  it  came  from  the  factory,  would  quit  after  about 
8  hours.  I  put  additional  feet  on  the  computer  to  increase  the  bottom 
clearance  and  found  that  it  would  last  for  about  17  hours.  Then  I  bought  a 
keyboard  into  which  I  mounted  the  computer.  Once  again  I  was  back  to  only 
8  hours  between  crashes.  I  then  cut  a  large  vent  hole  in  the  keyboard  case 
resulting  in  a  computer  which  would  run  for  24  hours.  This  was  not  adequate, 
so  I  moved  the  regulator  to  a  4  inch  by  4  inch  aluminum  plate  along  with  a 
heatsink.  Now  the  computer  keeps  going  for  approximately  2  days. 


My  fourth  computer  is  also 
mounted  in  an  aluminum  case  along 
with  the  keyboard.  I  placed  the 
regulator  on  the  case  with  a 
heatsink.  But  this  computer  would 
quit  after  about  8  hours.  It  was 
mentioned  at  the  June  user  meeting 
that  the  uncommitted  logic  array 
(ULA)  chip  gets  hot.  I  removed  the 
cover  of  this  fourth  computer  and 
felt  the  chip.  It  was  quite  hot.  I 
cut  a  piece  of  aluminum  channel  (2 
inches  by  1/2  inch),  applied  heatsink 
compound,  and  attached  the  heatsink 
to  the  ULA  chip.  With  this  change, 
the  computer  ran  for  12  days  before 
quitting . 


(Editor's  note:  As  reported  in  the 
June  newsletter,  Timex  has  recognized 
the  heating  problem  with  the  ULA 
chip.  The  chip  employs  bipolar 
technology  which  consumes  lots  of 
power  and  thus  the  chip  runs  hot.  To 
solve  the  problem,  Timex  is  install¬ 
ing  heat  sinks  on  the  ULA  chips.  The 
T/S  1500  logic  chip  employs  CMOS 
technology  and  should  not  over-heat.) 


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©1983  by  KOPAK,  Inc.  all  rights  reserved 


5 


BUFFERING  THE  DATA  BUS 


In  this  article,  an  approach  to  buffering  the  data  bus  is  described. 

This  approach  entails  modifying  the  internal  circuitry  of  the  computer, 
replacing  passive  components  (resistors)  with  two  logic  chips. 

The  data  bus  is  the  name  used  for  eight  specific  input  and  output  signal 
paths  in  the  Sinclair-Timex  computer.  Almost  every  piece  of  information 
processed  by  the  computer's  Z-80  processor  flows  along  these  signal  paths. 

The  data  bus  extends  from  the  Z— 80  microprocessor  chip  through  various 
internal  circuits.  It  terminates  on  the  edge  connector  on  the  rear  of  the 
computer . 


When  peripheral  devices  are  attached  to  the  computer,  it  is  often 
necessary  to  buffer  the  signals  on  the  data  bus.  Buffering  entails  placing 
circuitry  on  the  signal  paths  which  isolate  or  eliminate  undesired  signals  and 
amplify  or  enhance  desired  signals.  Buffering  is  usually,  but  not  always, 
provided  in  commercially  available  peripheral  devices.  If  you  plan  to  design 
your  own  devices,  you  will  need  to  have  buffering  circuits. 

The  buffering  approach  described  here  is  currently  in  operation  on  a 
MicroAce  computer.  The  MicroAce  is  similar  in  design  to  the  ZX-80  and  early 
ZX-81s.  It  was  sold  by  mail  order  in  the  U.S.  Our  approach  should  be 
applicable  to  the  ZX-81  and  T/ S  1000,  machines  with  the  uncommitted  logic 
array  (ULA)  chip.  However,  some  additional  circuitry  is  required. 


In  the  Sinclair-Timex  computer,  the  data  bus  is  actually  separated  into 
two  buses.  On  a  schematic  these  are  designated  as  D  D  '  ....  D  '  and 


G>OS 


Dl>  D2>  •••»  i*e.,  primed  (') 

and  nonprimed  signal  paths. 
Separating  the  primed  and  nonprimed 
data  buses  is  a  set  of  resistors. 

The  value  of  these  resistors  is 
1  kilohm  in  the  earlier  computers, 
470  ohms  in  later  ones.  The 
separation  of  the  data  bus  into  two 
parts  was  done  because  of  the  unique 
way  in  which  the  computer  generates 
the  television  display — the 
processor,  or  nonprimed,  side  of  the 
bus  executes  NOP  (no  operation) 
instructions  at  the  same  time  as 
display  character  information  is 
being  transferred  on  the  primed 
side.  Because  of  this  approach, 
Sinclair  was  able  to  reduce  the 
parts  count  and  achieve  a  low  cost 
computer.  The  existence  of  the 
resistors  on  the  data  bus,  however, 
makes  it  more  essential  than 
otherwise  to  buffer  peripheral 
devices . 

The  figure  to  the  left 
illustrates  some  of  the  electrical 
connections  with  the  data  bus.  It 
shows  the  two  parts  of  the  data  bus 


6 


separated  by  resistors.  On  the 
Z-80  processor  side  of  the  bus 
are  the  NOP  function  and  the 
keyboard.  On  the  primed  side  of 
the  bus  are  the  ROM  and  RAM 
memory,  external  peripheral 
devices,  and  other  circuitry. 

Our  approach  to  buffering  the 
data  bus  is  to  replace  the 
resistors  with  an  octal  bus 
transceiver  chip  (a  2-way 
buffer),  such  as  the  74LS245. 


The  flow  of  electrical 
signals  through  the  resistors  is 
always  in  the  direction  dictated 
by  the  read  and  write  signals  of 
the  Z-80  processor.  Thus  the 
direction  of  propagation  for  the 
transceiver  chip  can  be 
controlled  by  the  Write  Enable 
(WR)  signal  from  the  processor. 

The  only  hitch  is  that  the  tranceiver  must  be  tristated  (electrically  removed 
from  the  circuit)  whenever  either  the  keyboard  buffer  or  NOP  function  are 
active.  With  the  MicroAce,  generation  of  the  signal  to  tristate  the 
transceiver  requires  only  one  chip.  More  logic  is  required  with  the  ZX-81  and 
T/S  1000  computers  because  certain  signals,  specifically  the  keyboard  scan  and 
NOP  signals,  are  not  output  by  the  ULA  chip. 

Above  is  a  schematic  of  the  required  circuit  for  the  MicroAce.  The  KBD 
signal  is  available  at  chip  Ull  pin  15  on  the  MicroAce  (this  is  the  same 
signal  as  on  IC  10,  pin  15  on  the  ZX-80).  The  NOP  signal  is  available  at  U16, 
pin  1  (IC  15,  pin  1  on  the  ZX-80).  In  the  MicroAce  it  was  possible  to  remove 
the  resistors,  bend  the  legs  of  a  socket,  and  install  the  74LS245  chip  where 
the  resistor  network  had  been  located*  The  74LS0Q  chip  can  then  be  mounted 
dead  bug  style  between  the  74LS245  and  the  Z-80  chip.  (A  dead  bug  mounted 
chip  is  one  that  is  turned  upside  down,  with  its  feet  sticking  into  the 
air  like  the  chip  pictured  in  the  last  newsletter.) 

The  schematic  below  shows  the  circuit  required  for  the  ZX-81  or  T/S  1000. 

It  should  work,  but  has  not  been  tested. 

a 


7 


REVIEW  OF  MASTER  MATH  by  Jack  Hill 


Master  Math  is  a  series  of  high  school  math  quizzes*  The  quizzes  come  on 
six  tapes,  four  programs  per  tape,  two  programs  per  side.  Each  program  is  a 
quiz.  Note  that  there  is  only  one  copy  of  the  program  on  each  tape,  so  if  one 
doesn't  load  you  will  need  to  get  a  replacement.  This,  in  fact,  happened  to 
me  and  the  distributor,  PMI,  promptly  replaced  the  tape. 

The  software  was  written  by  a  Ms.  G.  Ludinski,  a  math  teacher  in  England. 
Because  the  math  curriculum  in  England  is  slightly  different  from  that  in  the 
U.S.,  you  will  find  the  format  of  the  tape  slightly  different  from  what  you 
may  he  used  to.  I  found  this  to  be  no  problem.  Each  program  contains  two 
different  problems.  The  program  asks  a  question  and,  if  not  answered 
correctly,  give  the  formula  required  for,  or  the  method  of,  solving  the 
problem.  All  that  is  then  needed  is  to  plug  in  the  variables.  If  you  still 
answer  incorrectly,  the  program  prints  your  score  and  asks  if  you  would  like 
to  continue. 

The  subjects  included  are  algebra,  geometry,  trigonometry,  statistics, 
percentages,  indices,  and  elementary  calculus.  These  programs,  for  me,  were 
invaluable  in  reviewing  my  high  school  math.  But  they  do  contain  some  minor 
software  problems.  One  program  required  a  number  in  scientific  notation  for 
an  answer.  It  was  nearly  impossible  to  duplicate  the  exact  number  on  my 
calculator.  Another  program  would  not  accept  the  answer  X  when  the  computer's 
answer  was  IX.  All  the  programs  scrolled  correctly,  except  one  that  lacked 
the  appropriate  SCROLL  statement.  The  programs  are  written  in  BASIC,  but  are 
unlistable  due  to  a  short  machine  code  subroutine  that  is  invoked.  I 
discovered  how  to  defeat  the  protection  technique  and  listed  the  programs  so 
that  I  could  make  the  corrections.  A  salesman  at  PMI  told  me  that  they  will 
be  incorporating  these  changes. 

PMI  plans  a  series  of  quizzes  for  the  T/S  1000  and  the  upcoming  T/S  2000. 
The  tapes  sell  for  $9.95  apiece  or  $50.00  for  the  entire  set.  Because  of  the 
large  investment,  it  might  have  been  better  if  PMI  grouped  all  similar 
problems  together ,  instead  of  offering  a  sample  from  each  category  on  each 
tape.  The  tapes  can  be  ordered  from  PMI,  Inc.,  P.0.  Box  87,  Buckfield, 

Maine  04220,  telephone  1-800-227-1836. 

REVIEW  OF  VOTEM  by  Burt  Fisher 

VOTEM  is  an  analog  to  digital  converter  which  allows  you  to  measure 
voltages,  temperatures,  and  frequencies,  and  display  the  results  on  the 
television  screen.  Additionally,  it  is  a  signal  conditioner. 

My  main  purpose  for  the  purchase  of  the  unit  was  in  measuring 
temperature.  The  probe  is  sensitive  to  temperature  changes  as  small  as  1/100 
of  a  degree.  To  give  an  example  of  the  precision  of  the  unit,  the  high 
temperature  on  one  day  was  79.81  degrees  Fahrenheit  and  the  low  was  60.07. 

You  can  automatically  record  temperature  at  any  interval  from  1  second  to 
hours,  retain  50  readings  in  2K  of  RAM  memory  (more  with  extra  RAM),  and  plot 
the  readings  against  time.  All  calibration  is  done  in  software.  The  manual 
is  well  done,  with  sample  programs. 

The  operating  principle  of  VOTEM  is  simple — it  uses  a  frequency 
converter.  Thus,  for  example,  a  dc  voltage  of  1  volt  input  will  cause  the 
VOTEM  to  output  a  10,000  Hz  signal  (10,000  pulses  per  second).  The  computer, 
through  software ,  counts  and  converts  these  pulses  to  a  reading  of  temperature 
or  voltage.  If  the  input  voltage  goes  up  (down),  the  frequency  goes  up  (down) 
as  well.  The  temperature  probe  and  its  associated  circuitry  simply  produce  a 

8 


small  voltage  that  is  proportional  to  temperature .  Thus,  VOTEM  can  be  used  as 
a  thermometer,  voltmeter,  or  frequency  counter  for  pulse  rates  up  to  30  kHz. 
Potential  applications  of  VOTEM  include  hooking  it  to  a  photocell  to  measure 
solar  intersity  or  using  it  as  a  smart  thermostat  for  heating/cooling  control. 

In  addition  to  the  frequency  converter,  VOTEM  is  also  a  tape  conditioner. 
The  conditioner  function  allows  you  to  use  a  much  lower  setting  on  your  tape 
recorder,  potentially  improving  tape  loading.  It  also  has  a  light  emitting 
diode  and  earphone  output  for  monitoring  tapes  and  pulses.  VOTEM  is  made  of 
quality  components  and  took  me  just  90  minutes  to  assemble.  It  is  available 
for  $39.95  (kit)  and  $59.95  (assembled  and  tested)  from  Down  East  Computers, 
Box  3096,  Greenville,  North  Carolina  27834. 


ON  THE  TIMEX  PRINTER/MEMOTECH  MEMORY  COMPATIBILITY  PROBLEM 


Some  of  you  with  the  Memotech  64K  RAM  pack  and  the  Timex  printer  have 
found  an  incompatibility  between  these  periperals.  Bob  Smith  talked  with  a 
technician  on  Memotech" s  information  number  about  the  problem  and  was  given 
the  following  explanation  and  solution.  The  symptom  of  Bob's  problem  is  that 
the  keyboard  would  lock  up  after  a  period  of  time  when  he  was  running  with 
both  the  T/S  2040  printer  and  the  Memotech  64K  memory.  It  was  necessary  to 
reset  (unplug)  the  computer,  resulting  in  loss  of  program  and  data,  to  clear 
the  fault.  Memotech' s  technician  said  the  problem  was  with  the  printer,  not 
the  RAM  pack!  He  said  the  problem  was  caused  by  filtering  capacitors  added  to 
the  printer  to  reduce  radio  frequency  interference.  The  Memotech  solution  is 
to  clip  the  lead  on  end  of  the  capacitors  C4,  C5,  and  C6,  thus  removing  them 
from  the  circuit.  These  are  large,  well-marked  components.  Bob  has  not  tried 
this  fix  as  yet,  so  if  you  attempt  the  modification,  make  the  cuts  such  that 
you  can  repair  the  damage  in  case  it  doesn't  work. 


A  LARGE  60  KEY  TACTILE  FEEL  KEYBOARD 
(MEASURES  10”  x  4")  THAT  PLUGS  INTO  THE  SAME 
CONNECTORS  AS  EXISTING  KEYBOARD  ON  YOUR 
ZX81  OR  TIMEX  SINCLAIR  1000.  IT  HAS  ALL 
SILKSCREENED  LEGENDS  IN  3  COLORS  ON  THE 
BASE;  MOLDED  LEGENDS  &  GRAPHICS  ON  KEY  TOPS; 
8  AUTOMATIC  SHIFT  KEYS  (NO  SHIFTING  REQUIRED) 
FOR  EDIT,  DELETE,  SINGLE  &  DOUBLE  QUOTES, 
COLON,  SEMI-COLON,  FUNCTION  &  STOP;  5"  SPACE 
BAR;  2  SHIFT  KEYS;  NUMERIC  KEY  PAD. 


■■■■■ 

MASS.  RESIDENTS  ADD  5%  SALES  TAX 
SHIPPING  a  HANDLING  $4.00/UN!T 

QUANTITY  DISCOUNTS.  WE 
WILL  ACCEPT  MC/VISA.  PLEASE  INCLUDE  #’S,  EXP. 
DATE  AND  SIGNATURE.  FOR  MORE  INFORMATION 
SEND  SASE.  SEND  INQUIRIES,  CHECK  OR  MONEY 

ORDER  TO:  E-Z  KEY 

SUITE  75 

711  SOUTHERN  ARTERY 
QUINCY, MA  02169 


wm 

SERIOUS  PROGRAMMERS 

“MUST-HAVE"  UTILITIES 
For  ZX-81  and  T/S  1000  Computers 

FILE*SYS  (taat,  ttaxlbt*.  r.Nable)  _ 

_  Read/ Write  Cassette  Data  Tape  Files 

FILE*  BASIC  Onclodaa  FH.E«8YS  functions)  *^5 
Save/Merge/Erase  BASIC  Segments 

FILE*  VARS  (r.qoir.s  FILE*SY8  or  "BASIC)  $  5 
Save/Restore  Strings  &  Arrays 

BASIC* OLAY  (parmtt*  ful  uaa  of  #4K  RAM)  *-jq 
_  Overlay/Copy  BASIC  Segments 

COPY  *  (dupfcatea  protect  ad  tapM)  $10 

Copy  Standard  Cassette  Tapes 

HEXAS*  (generates  relocatable  code)  $10 
Symbolic  Hex  Assembler  -  on  basic) 

LOGIC*  (provide#  true  logic  functions)  £  c 

_ AND,  OR,  XQR,  NOR,  HAND,  NOT  *  ° 

-  Sisnpie  user  Interface  via  USR  function 
-Wei -documented  user  manuals 

-  On  tape  cassette  in  relocatable  machine  language 

Check  or  MO  delivers  now 

SirL.W.re  SASE  for  Info. 

6  Turning  Mill  Road,  Lexington,  MA  02173 


9 


COMPUSERVE  IS  TERRIFIC  by  Jack  Hodgson 

It  is  perhaps  best  to  think  of  CompuServe  as  a  great  big  electronic 
library  accessed  by  a  computer  and  modem.  This  is  gonna  sound  like  a  sales 
pitch  anyway ,  so  let  me  quote  from  their  brochure; 

Press  a  few  buttons,  and  find  out  about  the  latest  advances 
in  home  management  and  nutrition,  recent  business  mergers, 
and  high  school  sports  scores.  Gather  updated  information — 
a  process  that  used  to  require  hours  of  painstaking 
research  directly  from  your  home  or  office.  Communicate 
with  business  associates  in  other  parts  of  the  country, 
instantly  and  economically.  Match  wits  with  CIS  (CompuServe) 
in  computer  game  competition.  We  think  you'll  agree  the 
capabilities  of  CIS  are  almost  endless. 

CompuServe  is  very  easy  to  use.  Everything  is  accessed  with  a  pyramid  of 
easily  understood  menus.  After  a  couple  of  times  on  the  system,  you'll  be 
able  to  save  time  by  GOing  directly  to  the  subject  or  page  number  you  want. 

You  can  look  at  all  kinds  of  information  from  the  AP  News  wire  and  stories 
from  the  Washington  Post  to  CompuServe's  own  movie  reviews  and  magazine.  Today. 

One  thing  that  is  particularly  exciting  on  CompuServe  are  the  Special 
Interest  Groups  or  SIGs.  There  are  SIGs  covering  topics  from  medical  and 
legal  through  health,  environment,  and  food.  There  are  also  computer  SIGs  for 
all  types  of  machines  and  applications.  And,  if  you  think  there's  one  they've 
left  out,  tell  them.  They  may  let  you  start  it. 

The  SIGs  have  three  main  parts.  First,  there  is  a  message  section  where 
you  can  read,  leave,  and  reply  to  messages.  You'll  find  an  active  exchange  of 
information  relating  to  the  particular  interest.  Second,  there  is  a  database 
containing  articles,  lists  of  resources,  and,  in  computer  SIGs,  public  domain 
software.  And  in  the  third,  and  perhaps  the  most  exciting,  part  there  is  an 
on-line  conference  area.  You  can  hold  live  conversations  with  other  SIG 
members  from  around  the  country.  Patterned  after  Citizen's  Band  radio  (CB) 
open  channel,  the  transmissions  of  participants  scroll  up  your  screen  and  you 
are  able  to  speak  by  simply  typing  on  your  keyboard. 

Especially  exciting  to  us  Sinclair-Timex  fans  is  that  there  is  a  SIG 
subgroup  specifically  for  Sinclair  and  Timex  computers  (GO  CEM-450).  In 
addition  to  the  message  board  and  database  area,  this  SIG  holds  a  regular 
weekly  meeting  on  Wednesdays  at  10:30  p.m.  (Eastern  Time)  where  users  get 
together  to  exchange  information  and  gossip  about  the  Sinclair-Timex 
community.  There  are  many  lighter  moments.  Although  few  members  have  met 
face  to  face  or  talked  by  phone,  they  know  each  other  fairly  well  and  often 
engage  in  some  friendly,  non-computer  related,  banter. 

One  Wednesday  night  recently,  after  our  regular  monthly  BCS  meeting,  Sue 
Mahoney,  Cliff  Danielson,  and  I  adjourned  to  my  home  where  we  logged  onto 
CompuServe  and  joined  the  SIG  meeting  in  progress.  We  spoke  with  Sinclair- 
Timex  users  in  New  Jersey,  Colorado,  Oklahoma,  Arizona,  California,  and 
Virginia,  simultaneously.  Taking  turns  at  the  keyboard.  Sue,  Cliff,  and  I 
participated  in  a  lively  conversation  about  the  Sinclair-Timex  community  and 
how  it  is  evolving. 

My  only  reservation  about  CompuServe  is  that  the  cost  ($5  per  connected 
hour)  can  add  up  quickly,  especially  on  the  CB  channels.  But,  with  a  little 
discipline,  it  can  be  a  real  valuable  resource  and  lots  of  fun. 


10 


REVIEW  OF  BOUNCY  by  Beth  Elliott 

As  far  as  ZX-81  and  T/S  1000  arcade  games  have  gone,  I  haven't  seen  a 
whole  lot  of  intriguing  fast  action.  Bouncy,  for  one,  can  perform  on  the 
arcade  level. 

Here's  the  setup  of  Bouncy:  Your  ship  is  trapped  within  the  confines  of 
the  screen  and  you  must  fight  off  the  bouncing  attack  balls  while  your  oxygen 
supply  is  constantly  depleting.  You  fire  by  hitting  any  key  other  than  the 
direction  arrows.  Horizontal  motion  of  the  ship  is  achieved  using  right  and 
left  arrow  keys.  Points  are  accrued  through  destruction  of  the  attack  balls. 

Up  to  five  balls  appear  on  the  screen  at  any  one  time.  The  balls  reflect  off 
the  walls  of  the  screen.  They  are  slow  but  challenging  moving  targets.  You 
can  replentish  your  oxygen  supply  by  seizing  one  of  the  oxygen  ships  as  it 
periodically  moves  across  the  top  of, the  screen.  The  game  ends  when  you  have 
either  exhausted  your  oxygen  supply  or  your  supply  of  three  ships.  The  top  of 
the  screen  indicates  round,  high  score,  current  score,  and  oxygen  level. 

Bouncy  requires  16K  RAM  memory.  It  runs  automatically  after  loading.  I 
had  some  difficulty  replaying,  which  may  have  been  due  to  the  computer  I  was 
using.  Written  instructions  are  not  necessary  because  the  instructions  on  the 
screen  are  sufficient  to  begin  playing.  The  game  starts  and  runs  quickly. 

The  startup  display— the  head  of  Count  Von  Der  Bouncy — is  impressive.  But 
unfortunately  it  is  only  seen  upon  loading,  not  for  replays.  The  author  makes 
very  good  use  of  moving  graphics.  I  recommend  this  game. 

Bouncy  can  be  obtained  for  $7.95  from  Infinity  Research  Development,  845 
Via  de  la  Paz,  Suite  A120,  Los  Angeles,  California  90272.  Infinity  also  has  a 
number  of  other  fast  action  games. 

***  ZX  PRO/FILE  *** 
a  16K+  file  manager  for  the  Timex 

ZX  PRO/FILE  is  a  machine  language  data  base 
that  gives  you  tremendous  versatility: 

*instant  access  to  any  file  stored  in  memory 
*files  of  any  size  in  the  same  program  run 
^single  or  multiple  word  search  capabilities 
^ordered  file  displays 

^comprehensive  programmable  printer  functions 

A  59  page  manual  comes  with  the  cassette.  In  it 
are  complete  instructions,  examples,  directions 
for  upgrading  to  larger  memories,  modifications, 
program  listings,  and  a  detailed  explanation  of 
how  the  program  works.  There’s  even  an  intro¬ 
duction  to  machine  coding  for  beginners. 

ZX  PRO/FILE  is  the  best  file  manager  you  can 
get  for  your  Timex.  In  fact,  users  report  that  it 
provides  data  handling  functions  found  only  on 
the  most  sophisticated  systems. 

Price:  just  $16.95 

Let  me  send  you  full  specifications.  Write  to: 

Thomas  B.  Woods 
P.O.  Box  64,  Jefferson,  NH  03583 
Phone:  (603)  586-7734 


WHAT  DO  YOU  WANT 
FOR  YOUR 
TIMEX  SINCLAIR? 

•  Applications 
®  Utilities 

•  Games 

•  Expansions 

•  News  and  Reviews 

•  Practical  Advice 

Get  all  this  every  month  with  SYNTAX  newsletter. 
Everything  you  need  to  get  the  most  from  your  ZX/TS 
computer.  Just  $29  for  a  full  year  of  SYNTAX, 
devoted  to  your  computer. 

Order  yours  today. 

^  617/456-3661 
MC/VISA/AMEX/DINERS 


6 


SYNTAX  RD  2  Box  457, 
Harvard,  MA  01451 


n 


FOR  MORE  INFORMATION 


Sue  Mahoney,  Director  of  the  Sinclair-Timex  User  Group 
c/o  The  Boston  Computer  Society  or  call  (203)  573-5816 

Jack  Hodgson,  Publisher,  (617)  354-7899 
P.0.  Box  526,  Cambridge,  MA  02238 

Cliff  Danielson,  Editor,  (617)  256-4638 
14  Davis  Road,  Chelmsford,  MA  01824 

John  Kemeny,  Contributing  Editor  and  User  Group  Correspondent 
284  Great  Road,  Apt •  D5,  Acton,  MA  01720 

Beth  Elliott,  Librarian,  (617)  742-4826 

c/o  Sinclair  Research,  50  Staniford  Street,  Boston,  MA  02114 
Allan  Cohen,  Meeting  Coordinator,  (617)  961-3453 


ADVERTISE  IN  THE  SECOND  ANNIVERSITY  ISSUE 
Computer  Related  Products  and  Services  Only 
Open  Rate:  $40  per  Quarter  Page 
For  Rate  Card  and  Discount  Information  Contact  the  Publisher 


DIRECTIONS  TO  THE  SEPTEMBER  MEETING:  The  Sinclair-Timex  User  Group  meets  in 
the  Large  Science  Auditorium  (Room  8/2/009)  of  the  University  of  Massachu¬ 
setts  of  Boston,  Harbor  Campus.  The  Harbor  Campus  is  only  3  miles  from 
downtown  Boston  and  easily  accessible  by  public  and  private  transportation. 
From  the  north  or  west,  take  the  Southeast  Expressway  to  Exit  17.  Turn  left 
onto  Columbia  Road.  Follow  construction  signs  to  Morrissey  Boulevard  in  the 
direction  of  UMASS  and  the  Kennedy  Library.  Turn  left  at  the  light  into  the 
Campus.  From  the  south,  take  Morrissey  Boulevard  northward  to  the  campus.  On 
the  MBTA,  take  the  Red  Line  (Ashmont  Train)  to  Columbia  Station.  Transfer  to 
the  free  University  shuttlebus  in  the  T  parking  lot. 


OOTTie  Boston 
OO  Computer  Society 

Three  Center  Plaza 
Boston,  MA  02108 
617-367-8080 


Nonprofit 
U  S.  Postage 
Paid 

Permit  1 1 38 
Boston,  MA 


Circle  Chess  Group 
^ •  Stanonis 
P.0.  Box  63 

Des  Plaines,  IL 

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60017